Floating form: stipe 13-20 cm long. Leaflets obtriangular in outline, usually hairless, outer margin rounded, subentire to bilobed. Dry land form: stipe 15-12 cm long. Leaflets 5-15 x 2-11 mm, outer margins bilobate to shallowly incised , rarely entire, thinly set with long hairs to hairless. Sporocarps: solitary, 5-7 x 3.5-4.8 mm; rectangular to bean-shaped in outline, flanks concave, grooved dorsally, ventrally and distally, densely set with long hairs when young, at maturity becoming hairless and almost black; lower tooth absent, upper tooth prominent, sharply acute, usually somewhat curved. Pedicels 6-17 mm long, erect, slender, slightly curved, free, arising from the axil of the stipe.

Sporocarps are produced on dry land only.

unicornis: one horn; a reference to the single, prominent upper tooth on the sporocarp of this species.

Along sandy riverbeds, in vleis and along the margins of seasonal pools in semi-arid scrub and Acacia-dominated woodland.

See African distribution.

Angola, Namibia.

Aquatic, terrestrial.